Fluid machines

ABSTRACT

A rotodynamic pump includes a pump casing housing a shaft mounted impeller, which shaft is driven by a suitable drive motor, and suction and discharge ducts in the pump casing; and pipelines are provided for the supply and discharge of fluid to and from the suction and discharge ducts respectively. By the present invention, the pipelines are fixedly carried on a frame which is supported by any suitable base member for example, by the pump drive motor, such that load on the frame is not transmitted to the pump casing, and branch conduits connect the support member and the ducts for continuity of pipeline to the ducts. The arrangement enables the pump casing to be free of pipe load and the pump to be removable in toto or in part without disturbance to the pipelines; also thermal loads due to differential thermal expansion between the frame and pump casing are not transmitted to the pump casing.

United States Patent 1191 Anderson 1 Mar. 25, 1975 FLUID MACHINES 645,921 11/1950 United Kingdom 415/108 838,317 6/1960 United K dom.... 415/201 [75] Inventor g g g g Anders, 629,667 4/1933 oerniany .%ili; .1 415/201 as w, co an r [73] Assignee: Weir Pumps Limited, Glasgow, Primary ExaminerHenry F. Raduazo Scotland Attorney, Agent, or FirmMason, Fenwick & 22 Filed: Sept. 17, 1973 Lawrence [21] Appl. No.: 397,626 57 ABSTRACT A rotodynamic pump includes a pump casing housing [30] Foreign Application Priority Data a shaft mounted impeller, which shaft is driven by a Sept. 23 7 United Kingdom 44122/72 suitable drive motor, and suction and discharge ducts in the pump casing; and pipelines are provided for the 52 U.S. c1 417/360, 415 201, 248/2, pp and discharge of fluid t9 and from the Suction 417/423 R and discharge ducts respectively. By the present in- 511 1111. c1. F04b 17/00, F04d 29/60 vehtioh, the Pipelines are fixedly carried on a frame [58] Field 61 Search 415/201, 108; 248/2, 14; which is Supported y any Suitable base member for 417/360 423 R example, by the pump drive motor, such that load on the frame is not transmitted to the pump casing, and 5 References Ci branch conduits connect the support member and the ducts for Continuity Of pipeline to the ducts, The ar- 7 I rangement enables the pump casing to be free of pipe ri Ct load and the pump to be removable in toto or in part 6,1 g without disturbance to the pipelines; also thermal 3 457 869 7 1969 1216612111,, 415 201 loads due differential thermal expanslm between the frame and pump casing are not transmitted to the FOREIGN PATENTS OR APPLlCATlONS pump Casing 124,621 9/1931 Austria 415/201 378,906 8/1923 Germany 415/201 4 Clam, 3 Drawmg F'gures 4 -1 37 2 \C\ I\\\ 9 \f\\ 5% Q i y X 351 3 I ea 12 1; F 28 24 2/ 21/9 2/ 3 27 /4 fl: I: f f

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PATEMED MAR 2 5 I975 SHEET 2 [If 2 FLUID MACHINES The present invention relates to a fluid machine of the type including a casing and a fluid duct in the casing for the inflow or discharge of fluid from the casing, and particularly to a fluid pump. Such a machine is hereinafter referred to as a fluid machine of the type aforesaid.

In previous fluid pumps the pipework for the inflow and discharge of fluid from the pump casing was directly coupled to the casing at pump suction and discharge ducts so that the casing had to withstand the pipe load arising for example from pipework distortion, thermal loading and flange tightening. Aggressive materials attack pump components by corrosion and/or abrasion, and pump casings for such duties may require to be of expensive metal, plastics or ceramics. It has been a disadvantage that to cater for the pipe loads, the pump casing had to be of an unnecessarily greater thickness of expensive metal, plastic or ceramic or there had to be provided an outer sheath of cast iron moulded onto the casing which arrangement was expensive. Further, in previous pumps loads due to differential thermal expansion has been transmitted to the pump casing.

lt is an object of the present invention to obviate or mitigate the above disadvantages.

According to the present invention there is provided a pump installation including: a pump comprising a casing having a removable front cover and a back wall, an impeller shaft penetrating the back wall of the casing, sealing means sealing said penetration of said back wall, a rotary impeller mounted on said impeller shaft inside the casing, a fluid suction duct in the casing for delivery of fluid to said impeller, an inlet to said fluid suction duct located in a lateral wallof the casing, a fluid discharge duct in the casing for discharge of fluid from the impeller, and an outlet from said fluid discharge duct located in said lateral wall of the casing; a motor having a casing and being connected to the impeller shaft for driving the pump; bracket means rigidly interconnecting the motor and pump casings; a support member formed by an extension of said bracket means and adapted to fixedly carry pipes such that the pump casing is substantially free from pipe loads and thermal loads due to differential thermal expansion between the pump casing and the support member; and conduit means interconnecting the support member and said inlet and outlet; whereby on removal of said front cover said pump can be disassembled without disturbance to the pipes.

A embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings, in'which:

FIG. 1 shows a cross-sectional elevation of an electric-motor driven pump installation according to one embodiment of the present invention:

FIG. 2A is a sectional end view of the pump of FIG. 1 taken along the line 2A-2A in FlG. 1 looking in the direction of the arrows; and FIG. 2B is a sectional end view of the pump of HO. 1 taken along the line 2B-2B in FIG. 1 looking in the direction of the arrows.

Referring to FIGS. 1 and 2, a rotodynamic fluid pump 1 which is driven by an electric motor 9 includes a cylindrical casing 2 housing the pump impeller 3 and having a back wall 2a, and a suction casing part 4 abutting an outer end of the cylindrical casing 2 and aligned with the impeller eye 5. An annular suction plate 6 located at the eye of the impeller 3 is carried in an annular shoulder 7 of the casing 2 and is held in position by means of the suction casing part 4, preferably cooperating with a slight recess or shoulder area 6a on the suction plate 6. The pump casing parts 2, 4 are carried by a cylindrical bracket 8 supported by the motor 9, one flanged end wall 10 of the bracket being bolted to a flanged wall 11 of the motor. The casing parts 2, 4 are held in abutting relationship by means of long tie bolts 12 fixed to a flanged end wall 13 of the bracket 8.

The impeller 3 is secured to one end of the impeller stub shaft 14 by means ofa nut 15 which is covered by a domed cover l6'assisting the smooth inflow of fluid to the impeller eye 5 and the shaft 14 which extends into the bracket 8 includes a sleeve part 17 against an end wall of which an internal flange part 18 of the impeller is held by the nut 15. The other end of the stub shaft 14 is in the form of a large diameter cylindrical socket portion 19 receiving the motor drive shaft 20, and the shafts 14, 20 are drivingly coupled by means of key 21, a set pin 22 and countersunk screw 23 being provided to set the shaft 20 in the socket portion 19. Sealing rings 24 seal the shaft 20 and socket portion 19 interfaces.

The penetration of the radial back wall 2a casing 2 by the shaft 14 is sealed by means of a sealing gland 26 including a gland housing 27 housing chamber 30 for sealing medium, a sealing ring 34 for the chamber 30 located by gland nut 31, and a chamber inlet 35 in the housing 27 to which sealing medium is supplied via pipeline 36. The gland 26 is held securely in position by means of puller block 32 which serves to urge a radial flange 28 of the housing 27 into abutment with an internal flange 29 of the back wall 2a, the block 32 including an inclined shoulder 33 engaging a corresponding shoulder on the gland housing 27.

The pump 1 is particularly intended for pumping liquids of an aggressive nature which liquids attack the pump parts by corrosion and/or abrasion, and consequently the pump parts are made ofa suitable material for example a metal, plastics or ceramic material capable of withstanding such liquids. Since a suitable metal may be expensive, the casing parts if made of metal would be made as thin as possible commensurate with withstanding the required pump pressures, and such a casing would not be suited for carrying the pipe loads, as would one made from plastics or ceramic materials. Consequently in the present arrangement a separate pipe support member isprovided to withstand the pipe thrusts or loads, while it is arranged that the pump casing need only withstand the pump pressure.

The pipe support member is comprised by a flanged extension 37 of the bracket 9, the extension 37 lying adjacent the pump suction and discharge ducts 38, 39 with the axes of the ducts 38, 39 normal to the flange (see H0. 2), ln this pump embodiment, the inlet and discharge ducts 38, 39 extend substantially radially relative to the pump casing 2 and parallel to each other. the inlet duct 38 being included in the suction casing 4 while the pump casing 2 houses the discharge duct 39. Through bores 40, 41 in the flange 3'7 align with the ducts 38, 39, and flanged parts of the inlet and discharge pipes (not shown) for the pump are bolted to the extension 37 in alignment with the through bores 40, 41. Each duct 38, 39 includes an outer stepped part 42 housing a cylindrical branch conduit 43 which extends into a respective through bore 40, 41 to provide for continuity of the pipeline tothe duct 38, 39, and preferably each through bore has an outer recess 44 housing a sealing ring 45 engaging the flange of the respective pipe for sealing of the pipe/extension interface. Further, each cylindrical branch conduit 43 includes a pair of O-seal rings 46 engaging the duct wall and the sealing ring respectively. The flanged extension 37 (bracket 8) may be made of cast iron or other suitable material. It will be clearly seen therefore that flanged extension 37 carries the pipeline load while the pump casing need only withstand pump pressure. Further the motor and pump (unit) can be mounted on a common support, for example with the pump I extending in cantilever manner, and this conveniences alignment of parts during assembly work: the bracket 8 however provides a rigid connection between the motor 9 and the pump 1.

A very advantageous feature of the above pump according to the present invention, is that the pump can be removed (either completely or in part), without disturbing external pipework, removal of the bolts 12, front cover 4 pipeline 36, and impeller nut permitting the suction plate 6, impeller 3, stub shaft 14 and gland seal 26 to be removed by a front pull out" while the pump casing 2 is held axially by branch conduit 43 and radially by a small locating spigot or shoulder 2b (exaggerated in FIG. 1) on the pump casing and the support frame wall 13. The pump front cover or suction casing portion 4 may be removed by unscrewing the bolts 12 and then moving the cover axially so that it is free from engagement with the small spigots or shoulders 6a (FIG. 1) on the annular suction plate 6. This also then enables the cover 4 to be pulled downwardly out of engagement with one of the two branch conduits 43.

Due to the resilience of the sealing rings 45 and 46, the conduit 43 does not prevent the cover 4 from being moved in an axial direction by the small amount required to achieve this. After the suction plate 6, impeller 3, stub shaft 14 and sealing gland 26 have been withdrawn the removal of the casing portion 2 is similarly effected by moving it out of engagement with the shoulder or spigot (exaggerated in size) so that the casing 2 can be dropped down until it is disengaged from the other of the pipe conduits 43.

The foregoing construction and ease of disassembly is particularly advantageous in large pumps where the pump casing 2 is of such a mass as to be only practicably removable by means of a crane, and where the only maintenance required is say gland maintenance. Also, the branch conduits 43 float in their housings, so enabling differential thermal expension between the pump casing 2 and the pipework (and extension 37) when the pump is handling hot liquids. Since access to the pump is achieved by a rightward movement (as seen in FIG. 1 )of the suction casing 4, corrosive liquid spillage onto the motor/pump support on disassembly of the pump can be conveniently minimised by suitable location of the support e.g. by locating the support beneath the motor.

It will be understood that modifications are possible in the above described motor/pump installation according to the present invention without falling out with the scope of the present invention as defined by the appended claims, and particularly as regards the arrangement of the fluid conduit to the suction and discharge ducts of the pump.

I claim:

1. A pump installation including:

a pump comprising a casing having a removable front cover and a back wall, an impeller shaft penetrating the back wall of the casing, sealing means sealing said penetration of said back wall, a rotary impeller mounted on said impeller shaft inside the casing, a fluid suction duct in the casing for delivery of fluid to said impeller, an inlet to said fluid suction duct located in a lateral wall of the casing, a fluid discharge duct in the casing for discharge of fluid from the impeller, and an outlet from said fluid discharge duct located in said lateral wall of the casing;

a motor having a casing and being connected to the impeller shaft for driving the pump;

bracket means rigidly interconnecting the motor and pump casings;

a support member formed by an extension of said bracket means and adapted to fixedly carry pipes such that the pump casing is substantially free from pipe loads and thermal loads due to differential thermal expansion between the pump casing and the support member;

and conduit means interconnecting the support member and said inlet and outlet;

whereby on removal of said front cover said pump can be disassembled without disturbance to the pipes.

2. A pump installation as claimed in claim 1, wherein the support member has through bores to permit fluid communication between the pipes and said ducts, and the conduit means includes cylindrical branch elements each of which extends into a respective one of the through bores to form a continuous fluid conduit with one of the pipes.

3. A pump installation as claimed in claim 1, wherein a socket is formed in said inlet and said outlet to receive said cylindrical branch elements.

4. A pump installation as claimed in claim 3, wherein the through bores each have a stepped socket portion housing, a sealing ring for engagement with one of the pipes to seal it to the support member. 

1. A pump installation including: a pump comprising a casing having a removable front cover and a back wall, an impeller shaft penetrating the back wall of the casing, sealing means sealing said penetration of said back wall, a rotary impeller mounted on said impeller shaft inside the casing, a fluid suction duct in the casing for delivery of fluid to said impeller, an inlet to said fluid suction duct located in a lateral wall of the casing, a fluid discharge duct in the casing for discharge of fluid from the impeller, and an outlet from said fluid discharge duct located in said lateral wall of the casing; a motor having a casing and being connected to the impeller shaft for driving the pump; bracket means rigidly interconnecting the motor and pump casings; a support member formed by an extension of said bracket means and adapted to fixedly carry pipes such that the pump casing is substantially free from pipe loads and thermal loads due to differential thermal expansion between the pump casing and the support member; and conduit means interconnecting the support member and said inlet and outlet; whereby on removal of said front cover said pump can be disassembled without disturbance to the pipes.
 2. A pump installation as claimed in claim 1, wherein the support member has through bores to permit fluid communication between the pipes and said ducts, and the conduit means includes cylindrical branch elements each of which extends into a respective one of the through bores to form a continuous fluid conduit with one of the pipes.
 3. A pump installation as claimed in claim 1, wherein a socket is formed in said inlet and said outlet to receive said cylindrical branch elements.
 4. A pump installation as claimed in claim 3, wherein the through bores each have a stepped socket portion housing, a sealing ring for engagement with one of the pipes to seal it to the support member. 